This invention relates in general to a greaseless door lock, and more particularly to a greaseless door lock which is mounted on a door of a railroad car to secure the door in an open position or a closed position.
The railroad industry employs a variety of railroad cars for transporting products. Many of these cars, such as boxcars or auto rack railroad cars, are enclosed to protect the products or vehicles being transported. Enclosed railroad cars generally include one or more sliding doors to provide access to the interior of the cars. The doors are generally mounted on upper and lower tracks which are attached to the frame of the car. The doors have conventional door locks to maintain the doors in an open position or a closed position. The conventional door locks must be lubricated with a standard lubricant such as grease. The grease attracts particles and other materials, generally creates a dirty environment and causes grease contamination in the interior of the cars.
This problem is especially undesirable in auto rack railroad cars which transport newly manufactured vehicles, including automobiles, vans and trucks. Auto rack railroad cars, known in the railroad industry as auto rack cars, often travel thousands of miles through varying terrain. The typical auto rack car is compartmented, having two or three decks or floors, a frame, two side walls, a roof and a pair of doors at each end of the car. The doors protect the auto rack car from illegal or unauthorized entry and prevent theft or vandalism of the vehicles. The doors also prevent flying objects from entering the car and damaging the vehicles. In transit, the doors are secured in the closed position. When the automobiles are being loaded or unloaded, the doors are secured in the open position. Examples of such doors for auto rack cars are generally illustrated in U.S. Pat. Nos. 3,995,563 and 4,917,021.
Each door in an auto rack car includes at least one door lock having a locking pin which engages a socket attached to the frame of the auto rack car. The grease and dirt builds up on these door locks, creates a dirty environment and causes grease contamination inside the auto rack cars which is highly undesirable for the transport of newly manufactured vehicles because the grease and dirt can damage the finishes of the vehicles. The grease also tends to drip or fall off the door locks onto the floor or door tracks of the auto rack car. Workers step in this grease and then track the grease into the new vehicles. Thus, the grease sometimes damages the interior carpeting in the new vehicles.
The Association of American Railroads (xe2x80x9cAARxe2x80x9d) requires that the door locks and rollers be lubricated or greased every twelve months or sooner if necessary. The AAR also requires that the date on which the doors and rollers are lubricated be painted on the inside of the auto rack cars for tracking purposes. This requires extensive tracking procedures for this regular maintenance which increases the cost of operating the auto rack cars and decreases the efficiency of the use of the auto rack cars.
Accordingly, there is a need for a door lock for railroad cars, and in particular auto rack cars which does not need to be lubricated on a regular basis.
The present invention solves the above problems by providing a greaseless door lock for railroad cars and particularly auto rack railroad cars which eliminates the need to use grease or another lubricant to lubricate the door locks. The greaseless door lock of the present invention generally includes a steel C-shaped bracket having a side wall and spaced-apart upper and lower end walls attached to and extending transversely from the side wall. A mounting plate is attached to the bracket. The upper and lower end walls include aligned apertures for slidably receiving a steel locking pin.
The preferred embodiment of the greaseless door lock includes two semi-clyindrical replaceable plastic bushings, bearing members or collars (primarily referred to herein as xe2x80x9cbushingsxe2x80x9d) mounted in each aperture to prevent the steel-on-steel contact between the locking pin and the inner edges of the end walls which defines the apertures. The locking pin maintains the bushings on the end walls in the apertures. The bushings are preferably molded from a polymer such as a moly disulfide filled nylon although they could be made from other suitable materials such as manganese, bronze, ceramics, UHMW polyethylene, delrin or urethane. The bushings eliminate the need for a lubricant between the steel locking pin and the steel end walls of the bracket. The greaseless door lock also includes a spring mounted on the locking pin, a washer mounted on the locking pin below the spring and a stop extending transversely though the locking pin below the washer, which co-act to provide the action for the locking pin.
The greaseless door lock may include an alternatively shaped bracket for different positions on the door and a further embodiment of the greaseless door lock of the present invention includes a cylindrical bushing, bearing member or collar maintained in each aperture by a locking clip.
It is therefore an object of the present invention to provide a greaseless door lock for doors on railroad cars.
Another object of the present invention is to provide a greaseless door lock for doors on railroad cars which eliminates the need to lubricate the door locks.